when, why;准关系代词有as, but, than。复合关系代词有 what, whatever, whoever, whichever 等。
关系代词who, whom, whose, which, that,具体用法见下表： 主语 宾语 定语 指人 指物
关系副词：where,when, why。 准关系代词：as, but, than。
引导名词性从句或状语从句复合关系代词：what,whatever, whoever, whichever。
who/that which/that (whom)/(that) (which)/(that) whose whose 1. 由who, whom, whose引导的定语从句
1）关系代词who用作主语，用于指人或家养宠物等。 主句 Who引导的定语从句 This is the man who helped me when I was in trouble. Is Sheba the dog who was run over and nearly killed last year? 2）关系代词whom用作宾语（口语中常可省略），或介词宾语，用于指人。在非正式英语中，关系代词who也可用作宾语。 主语 whom引导的定语从句 The doctor (whom) you are looking for The fellow to whom I spoke The man who I saw yesterday 谓语 is in the room. made no answer at first. is called Smith. 说明：口语中，介词加关系代词可将介词放到句末，同时省略关系代词。 例如：Simon is the person you should talk to.
3）关系代词whose用作定语，既可指人，也可指物。 主句 whose引导的定语从句 Do you know the man whose name is Wang Yu? Do you see the house whose windows are all broken? That's the student whose application we have just read.
2 由which引导的定语从句及the way后接定语从句
1）关系代词which指物，在从句中作主语、宾语及介词的宾语。 Which在从句中作主语 The building which stands near the river This is the car which cost me quite a lot. is our school. Which在从句中作宾语，常可省略 This is the museum (which) I visited last Sunday. Did you find the (which) you wanted? book 2）在the way后接定语从句有三种形式。 (/) I don't like the way that he speaks.我不喜欢他说话的那种方式。 in which 说明：英语中，the way后不能用how引导定语从句，因为how不能作关系副词，如不说\，但可以说\。这里，how引导的名词性从句作表语。
3. 由\介词+关系代词\引导的定语从句
1）在\介词+关系代词\引导的定语从句中，该介词或与前面名词词组的搭配有关，或与从句动词的搭配有关。
介词与前面的名词搭配有关 The room in which there is a machine This is the desk at which I always do my homework is my workshop. 介词与从句的动词搭配有关 The early birds can easily find insects on which they feed. Homer Epic(荷马史诗)is a wonderful book from which I have learned a lot. 注意：日常口语中也可将介词放到句末，同时省略关系代词。例如： This is the hotel at which we stayed. => This is the hotel we stayed at. This is the girl to whom I wrote. => This is the girl I wrote to.
「of whom(人) [of which(物)
2) 名词、不定代词或数量词+ of which/whom(此结构的of which, of whom修饰前面的名词，不定代词或数量词)。
名词/all/none/neither/ either/each, some/many/much/most/a number, both/several/a little/(a) few/one/two. + of whom(人) / of which(物) 主句 \名词/不定代词等+of Which\引导定语从句 He's written a book, the name of which I've forgotten. The book contains 40 poems, most of which were written when he was at college. We interviewed ten applicants, none of whom we thought was suitable. 3) of which/whom结构在从句中有以下两种表达形式。 主句 of which/of whom结构引导定语从句 the windows of which are all broken? Do you see the house of which the windows are all broke? He has two sons, neither of whom is tall. of whom neither is tall. 4 由in which case等引导的定语从句 1）以\介词 + which + 抽象名词（case, point, reason, situation, time 等)” 构成的从句用于总结主句的内容，对所提的事进行补充说明。句中的which用作定语。
主句 The bus may be late, He paused to examine his notes, Hard work changed her greatly, The violent storm roared all night,
\介词+ which +抽象名词\引导定语从句 in which case there's no point in waiting. at which point a loud crash was heard. for which reason we could hardly recognize her. during which time the ship turned upside down. 5. 由that引导的定语从句
1）关系代词that引导定语从句可以指人或指物，在从句中作主语或宾语，代替who, whom
或which。但不能作介词宾语。 This is the boy The young man The house The letter that引导定语从句（指代人或物） that/who broke the window. (that/who( m) ) you met yesterday that/which was built a century ago (that/which) I received just now is here right now. stood still in the quake was from my father. 2）下列情况常用关系代词that引导定语从句。
① 先行词是all, few, little, much, something, anything 等不定代词
The life that I have is all that I have. There was little that the doctor could do for her. Much that you have read is nonsense. ② 先行词被all, any, each, every, few, little, no, only, same, very等修饰(指人时有时也可用who)
I have read all the books that you lent me. That was the only chance that I could get. This is the very book that I am looking for. The pilot was the only man who survived. ③ 先行词被形容词最髙级修饰
It’s the most interesting book that I have ever read. This is the best TV set that is made in China. ④ 先行词被序数词修饰
The first lesson that I learned will never be forgotten. It is the last straw that breaks the camel's back. ! ⑤ 先行词是数词或被数词修饰
There are ten, not nine, that I found in the room. The two books that I bought yesterday are all novels. ⑥ 关系代词在限定性从句中作表语，可指物或指人
My hometown is not the poor area that it was. He is not the man that he was! ⑦ 先行词既有人又有物时
They talked about the things and persons that they could remember. ⑧ 在以 who，which，what 引起的问句中，为避免重复，常用that
Who is the man that is talking to John? Which of us that knows anything does not know this? What was it that you did last week?
6. 关系代词作表语或宾语补语的情况
1）关系代词who或whom不能用作表语。
2）在传统语法中，常用关系代词which作表语，既可指人，也可指物：指人时，一般指从事某种职业或有某种特性，品质或才能的人。which引导的定语从句可以是限制性的，也可以是非限制性的。
主句 Which在从句中作表语或补语 Anna is a vegetarian, which no one else is in our family. He is no longer the man which I thought him to be. He thinks fashion is just nonsense, which it is actually not. 3）在现代英语中，用关系代词that作表语指代人和物的现象越来越普遍，有些则认为一定要用that,在非正式文体中可省略。that的这一用法仅限于限制性定语从句。
主句 that在限制性从句中作表语 He is no longer the simple-minded man (that) he was five years ago. She's not the brilliant dancer (that) she used to be. My hometown is no longer the place (that) it was when I saw it ten years ago. 4）复合关系代词what引导的句子也常作表语，可指人或指物。 what引导的从句作表语 Things are not what they seem, She's not what she used to be, The most important thing is not what you say but what you do.
主句 7. 关系代词的省略
1）现代英语中，关系代词在从句中作宾语时往往省略，即使书面语中也是如.此。先行词为不定代词时几乎总是不用关系代词。
The girl (whom) you met yesterday lives next door. I will tell you everything (which/that) I know.
1) 关系代词在从句中作表语，常用that，且往往省略。
Harry Porter still talks like the man (that) he was five years ago. Isabel's changed. She is no longer the girl (that) she was. 2) 当定语从句为there be结构时，通常不用关系代词。
This is the fastest train (that) there is to Michigan.
Please show me the latest reference book there is on the subject.
I must make full use of the time there is left to me and do as much as I can for the people. 我要充分利用剩余时间尽我所能为民谋事。 3) 主句为there be结构时，事实上的主语后(即be动词后的名词或代词后) 若带有定语从句，作主语的关系代词有时可以省略。
There's something (that) keeps worrying me.
8. 由关系副词when, where, why引导的定语从句
关系副词when，where, why是兼有连词作用的副词，通常用于表时间、地点、原因等名词后，引导定语从句。
1）when: 引导定语从句，修饰具有时间意义的先行词，如time，hour, week, month, season, occasion等名词，也可用 \介词+ which\代替。口语中常省略when或用that代替。 主句 He still remember the time Summer is the season There are occasions I haven't seen them since the year 关系副词when引导的定语从句 when/at which he became a college student. when/in which many people go on vacation. when/on which joking is not allowed. when/ (/) /that they got married. 说明：先行词是表时间的名词时，用关系副词when,还是用关系代词that/which（或省略）引导定语从句，这要看它在从句中起副词作用作时间状语，还是起代词作用作宾语。例如： Do you remember the day when he came to see you. （when 作时间状语）
Do you remember the day (that) we spent in the woods, （that 作从句的宾语）
2）where:引导定语从句，修饰具有地点意义的先行词，如place, direction, room，building, school 等名词，或 case，point, position, situation, stage, state 等有地点含义的抽象名词，也可用\介词+ which\代替。口语中，当先行词是place， room 等时，可用that或省略where。
主句 Have you ever been to the farm This is the room This is the place We have now reached the point You are now in a position 关系副词where引导的定语从句 where/on which John is working? (where/ill which) Shakespeare was born. (where/that) we lived for 5 years. where/at which a change is needed. where you may lose a large sum of money. 说明：? 先行词是表示地点的名词时，用关系副词where,还是用that/which(或省略)引导定语从句。这要看它在从句中起副词作用作地点状语，还是起代词作用作宾语。
This is the house where we lived last year. 这是他去年住过的房子。(地点状语)
This is the house (which) he visited last year. 这是他去年参观过的房子。(代词作宾语) ? 比较:where作连词引导地点状语从句和条件状语从句。
Where others are weak, he is strong. 别人的弱点正是他的强项。（地点） Where there is a will, there is a way.有志者，事竟成。（条件） Where there is...there is（哪里有?哪里就有） ? 比较:where作连接副词引导名词性从句。
It's really none of your business where I spend my holiday.（主语从句） That's where you are wrong.（表语从句） I can't see him from where I am.（介词宾语）
Then arose the question where we can get enough money.（同位语从句）
3) why:只引导限定性定语从句，其先行词只有reason，且必须紧随其后，在从句中表原因，可用\代替，口语中可省略why。 Is this the reason That’s the reason The reason This is the reason 关系副词why引导从句 why you are so happy? (why) I'm checking it. why he failed in the competition for which he hates me is that he was too proud.
说明：? why在从句中作原因状语时，定语从句可以由下列3种表达形式。
The reason why I'm phoning you is to invite you to a party The reason that I'm phoning you is to invite you to a party The reason (/) I'm phoning you is to invite you to a party ? 先行词reason在从句中作宾语时，只能用that或省略，不能用why。
This is the reason (that) he explained to us at the meeting. The reason that he told us is not true.
I know that the reason he gave me is just an excuse.
9. 关系副词when, where, why的特殊用法
1） when, where, why前省略先行词的情况。
在 This is, That is, It is 后可省略先行词 the time, the place, the reason,直接跟 when, where, why，例如：